“…These ripples cause liquid microcirculatory currents close to the bubble wall 23 and shear forces on solid surfaces near the bubble, and these can be delivered onto a target down a water stream if the sound can be made to propagate down the stream 19 and if, at the target, it can generate the conditions needed to excite these waves. 24,25 Earlier studies found that by delivering shear and liquid microcirculatory currents at the end of a liquid stream, they could remove a range of contaminants from solid surfaces, including brain tissue from surgical steel, 26 bacteria from hay, 26,27 and marine biofilms from hull material. 28 It was noted that, if the surface is structured, contoured or contains crevices from which contaminant is difficult to remove and hence difficult to clean, acoustic forces will drive the rippling bubbles into pores to enhance cleaning.…”